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How is 3-D printing helping enhance MRI?

Technology has made large strides in recent years. In the past, 3-D models that could be printed at home were a dream for inventors to ponder in their free time. Innovations in recent years have made this dream a reality for many people. 3-D printing has begun to make its way into various fields, including healthcare. Since 3-D printing has become more widely available, it has begun to see uses in surgical training and planning, as well as patient communication. Each of these uses is still under research and may not be ready for clinical use.

MRI and 3-D printing

Magnetic resonance imaging (MRI) produces detailed images of tissue structures and organs in the patient's body. Throughout the course of the scan, magnetic fields that are generated by the super-conducting magnet inside the scanner undergo shifts due to pulse sequences. These shifts cause the protons to align inside the patient's body and then relax in time with the pulses. This causes signals to be emitted by the patient's body, which can then be received and translated into data through the MR receiver coils. Once the data enters the computer, it can be interpreted to create images. The radiologist then reads these images to get a better idea of what is going on in the body.

Each image from the MRI is called a slice and shows a different angle of the region of interest (ROI), which is the area that is scanned in the MRI and is being studied. These slices traditionally have helped surgeons prepare for their surgeries by providing visual maps of the patient's body. The images obtained during MRI scans can be combined using specific computer programs to create a 3-D image of the inside of the patient, such as a 3-D model of the kidney.1 This image can now be printed using a 3-D printer to create a model that is specific to each patient, which could help with training and planning for surgeons but is currently still being researched. Additionally, these models may help patients understand what is going on in their body and where the disease or disorder is affecting them.

Surgical training and planning

When a surgeon is being trained, they may use plastic models created from a generic mold to learn about their specialty. Often, these models lack realism, which has caused some teachers and professors to want to alter the models or create new ones. One of the biggest issues with the traditional models, as well as some of the new ones, is that they do not bleed like a person would during surgery. One team created potential models of the kidney to simulate this blood flow during the procedure.1 They then had five expert and ten novice surgeons attempt a challenging procedure on the model. The experts found the model to be very realistic, while the novices felt it was particularly helpful to practice on.

Similarly, another team tested the applications of 3-D printing in surgical planning and found that the models enhanced the surgeon's plans.2 Three surgeons were given 2-D MRI images and asked to create a surgical plan for 10 different kidney surgeries. At least a week later, they were given 3-D models of each of the patient's kidneys. Throughout all ten surgeries, at least one surgeons said that they would change their surgical plan based on the model. The surgeons also reported feeling more comfortable after having dealt with the 3-D models.

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Patient communication

There are multiple different ways to learn. Some people learn through reading, some through doing and others still through sight. All of these types of learners, but especially the visual ones, may benefit from these 3-D printed models. Having the ability to see and feel what the surgeon is talking about may make patients more aware of their surgery and provide a better understanding of the procedure. One study conducted took the survey responses of 200 patients after conferring with their surgeons based on imaging alone and 127 after imaging and again after using a 3-D model.3 In this study, the 3-D printed models performed better than images alone. Patients understood their disease, cancer size and location and treatment plan better with the use of the model. Additionally, the patients expressed greater comfort with their treatment plan and a greater understanding of their anatomy compared with augmented reality models.

3-D models created using either MRI or CT scans may increase the comfort of trainees, surgeons and patients. This is particularly useful for trainees when they are faced with models that can mimic the processes of the body, like blood pumping. Similarly, models of specific patients can help surgeons plan, because they provide an easy to see and experience model for the surgery. Finally, patients may benefit from a 3-D printed model of their disease to better understand their anatomy, their disease, and their surgical plan. With the increased comfort, the healthcare system may provide better experiences for each of the participants.

References

  1. How 3-D Printing Could Help Shape Surgery. The-Scientist.comhttps://www.the-scientist.com/news-opinion/how-3-d-printing-could-help-shape-surgery-66070. Last accessed July 9, 2019.
  2. 3D printed renal cancer models derived from MRI data: application in pre-surgical planning. Abdominal Radiology. https://link.springer.com/article/10.1007%2Fs00261-016-1022-2. Last accessed July 9, 2019.
  3. 4D flow MRI, 3D printing improve congenital heart surgery. AuntMinnie.comhttps://www.auntminnie.com/index.aspx?sec=sup&sub=adv&pag=dis&ItemID=124291. Last accessed July 9, 2019.